HOTIRAI KOMPYUTER

Hotirai kompyuter pas az mikroprotsessor elementi duyumi asosi hisobida meshavad. Vazifai asosii khotira az nigoh doshtani informatsiya iborat ast. Kompyuter yakchand namudi khotiraro dorad. Hotirai asosi, ki yagon kompyuter be on kor karda nametavonad, dar shakli mikroskhema (chip) sokhta shudaast. Hotirai asosiro ba khotirahoi favri va doimi taqsim mekunand. Ba gayr az khotirai asosi (dokhili, zudamalkunanda), kompyuter boz khotirahoi beruni (sustamalkunanda) dorad. Hotirahoi berunii kompyuter dar shakli diskhoi magniti va optiki, disketho, CD–ROM va lentahoi magniti sokhta meshavand. In namud khotiraho baroi duru daroz nigoh doshtan va az yak kompyuter ba digar kompyuter kuchonidani informatsiya khizmat merasonand.

Vohidi chenaki bahisobgirii informatsiyaro bit (bit –binary digit – raqami dui) meguyand, ki qimati on ba 0 yo 1 ba- robar ast. Kompyuter asosan na bo bit, balki yakbora bo 8 bit kor mekunad. Paydarpayii 8 bitro bayt (byte) meguyand. Dar yak bayt metavon yake az 256 simvolro (28=256) kodguzori kard. Masalan, kodi adadi 5 ba 00000101 va kodi harfi lotinii L ba 01001100 barobar ast. Baroi hamin ham, gunjoishi khotirai kompyuter niz bo baytho chen karda meshavad. Guftan mumkin ast, ki yak bayt ba yak simvoli matni barobar ast. Azbaski bayt ham chenaki nisbatan khurd ast, binobar on baroi ba hajmi khotirai kompyuter baho dodan az chenakhoi kalontari baynalmillali istifoda mebarand:

1. 1 Kilobayt (Kbayt) = 1024 bayt = 210 bayt;
2. 1 Megabayt (Mbayt) = 1024 Kbayt = 220 bayt;
3. 1 Gigabayt (Gbayt) = 1024 Mbayt = 230 bayt.

Hotirai favrii kompyuter – khotiraest, ki doimo bevosita bo mikroprotsessor saru kor dorad. Mikroprotsessor programmaho va malumothoi zaruriro az khotirai favri girifta, onhoro kor karda mebaroyad va natijahoi hosilshudaro boz ba on ravon mesozad. Unvoni «favri» gi riftani in khotira behuda nest. Surati kori in khotira

benihoyat baland buda, hangomi khondan va sabti informatsiya protsessor intizori namekashad. Vale hamin ki kompyuter khomush karda shud, hamai informatsiyai dar on mahfuzbuda nobud megardad. Hotirai favriro bo kalimai RAM (Qandom access memoqy – khotirae, ki hamesha dastras ast) ishorat mekunand.

Programmahoe, ki dar kompyuter istifoda burda meshavand, bevosita az hajmi khotirai favrii on (RAM) vobastaand. Hangomi khurd budani hajmi RAM, qismi ziyodi programmaho yo umuman kor karda nametavonand yo khele sust kor mekunand. Masalan, agar hajmi RAM to 1 Mbayt boshad, on goh dar chunin kompyuter tanho bo programmahoe

kor kardan mumkin ast, ki onho baroi muhiti sistemai operatsionii MS DOS sokhta shudaand. Baroi dar muhiti sistemai operatsionii Windows kor kardan, boyad hajmi

RAM aqallan ba 8 Mbayt barobar boshad. Agar on ba 16 Mbayt va ziyodtar barobar mebud, on goh dar Windows khele khub kor kardan mumkin bud. Baroi dar serveri shabakahoi lokali, bo informatsiyai grafiki, bo videofilmho va gayraho kor kardan, khotirai 32–128 Mbayt va ziyodtar lozim ast.

Baroi az khotirai favri boz ham teztar dastras namudani informatsiya dar baze kompyuterho khotirai makhsusi benihoyat zudamale istifoda burda meshavad, ki onro kesh–

khotira meguyand. Kesh–khotira dar bayni mikroprotsessor va khotirai favri joygir shuda, nuskhai baze uchastkahoi RAM-ro dar khud nigoh medorad. Mikroprotsessor pesh az

on ki informatsiyaro az khotirai favri kobad, avval onro dar kesh–khotira justuju menamoyad. Bo hamin usul vaqti miyonai dastraskunii informatsiya khele kutoh megardad.

Baroi kompyuterhoi dar asosi mikroprotsessori Intel– 80386 DX va Intel–80486 SX korkunanda hajmi kesh–khotira ba 64–128 Kbayt barobar ast. Kompyuterhoi Intel-80486 DX, DX2, DX4 va Pentium bo kesh–khotirahoi 256 Kbayt mujahhaz gardonida shudaand. Baroi kompyuterhoi dar bazai mikro- protsessori Pentium korkunanda va RAM – 32 Mbayt keshkhotiraashon boyad az 512 Kbayt kam naboshad.

Dar kompyuterhoi IBM PC hamchunin khotirai doimi mavjud ast, ki dar on hangomi sokhtani kompyuter baze informatsiyai zarurtarini sistemavi sabt karda shudaast.

Informatsiyai dar in khotira sabtshudaro bo yagon roh tagyir dodan mumkin nest, vale onro khondan mumkin ast. Hotirai doimiro bo kalimai ROM (read only memory – khotira tanho baroi khondani informatsiya) ishorat mekunand.

Dar ROM asosan programmahoi khizmatrasonandai sanjishii tarzi kori qismhoi kompyuter (testguzaronho), bakordarovarandai sistemai operatsioni va ijrokunandagoni funksiyahoi asosii amaliyoti dokhilkunikhorijkunii informatsiya nigoh doshta meshavand. Dar aksariyat mavridho mundarijai ROM–ro BIOS (BIOS) meguyand: BIOS – Basic Input–Output System – Sistemai baza-vii dokhilkuni–khorijkuni.

Ba gayr az RAM va ROM dar IBM PC khotirai nachandon kalone mavjud ast, ki on baroi nigohdorii parametrhoi konfiguratsiyai kompyuter khizmat merasonad. In khotira nimdoimi buda, onro bazan hamchun CMOS-khotira nom mebarand. CMOS nom giriftani in khotira ba on vobasta ast, ki on az rui tekhnologiyai SMOS (Complementaqy mataloxide semiconductoq) sokhta shuda, qobiliyati istemoli energiyai shiddatash khele pastro dorad. Azbaski CMOS– khotira bo akkumulyatori makhsus mujahhaz gardonida shudaast, binobar on informatsiyai dar on mahfuzbuda hangomi khomushkunii kompyuter tagyir nameyobad.

Baroi tagyir dodani parametrhoi konfiguratsiyai kompyuter dar BIOS programmai makhsusi tanzimkunii konfiguratsiya – SETUP mavjud ast. Az akkumulyatori CMOS– khotira soati kompyuteri niz bo quvvai barq tamin karda meshavad. Namudi digari khotira, ki dar IBM PC istifoda burda meshavad, videokhotira nom dorad. In khotira baroi nigohdorii tasviri informatsiyai ba ekranbarovaranda istifoda karda meshavad. Videokhotira odatan ba hayati videokontrollyor dokhil meshavad. Videokontrollyor – skhe-mai elektronist, ki baroi dar ekrani monitor khorij namudani tasviri informatsiyai az RAM giriftashuda khizmat merasonad.

 Savolho:

1. Vazifahoi asosii khotirai kompyuter az chi iborat ast?
2. Vohidhoi gunjoishi khotirai kompyuter kadomhoyand?
3. Kadom namudhoi khotirai kompyuterro medoned?
4. Baroi dar muhiti sistemai operatsionii MS DOS kor kardan, hajmi khotirai kompyuter boyad chi qadar boshad? Dar MS Windows chi?
5. Hotirai favri az digar khotiraho bo kadom khosiyathoyash farq mekunad?
6. RAM, ROM, Kesh–khotira va CMOS-khotira gufta kadom khotirahoi kompyuterro dar nazar dorand?
7. Videokhotira baroi chi khizmat merasonad?

 Suporish:

1. Matni mavzuro bodiqqat khoned va onro naql kuned.
2. Nomi khotirahoi kompyuterro dar shakli tablitsa biyored va vazifayu kharakteristikahoi onhoro nombar kuned.
3. Mafhumhoi bit, bayt, Kbayt, Mbayt va Gbaytro manidod kuned va buzurgihoi 125 Kbayt, 247 Mbayt, 369 mln bayt, 872 Gbayt va 613 mlrd bitro ba chenakhoi digar bargardoned.